This book is of that particular genre of chant book the aim of which is to clarify for the user the method of singing certain psalms by laying them out in a more-than-usually idiot-proof manner.

In the case of this book, being published in the year 1903, it is interesting to see from examination of its contents that at this time just prior to the Vatican Edition, Solesmes was already thinking in terms of basically the same system of accents & preparatory notes as would later appear in the Liber Usualis.

Be that as it may, the interesting point for me was that in its title, the book in question claims to give the psalms “juxta ritum Romanum simul ac Monasticum”, or in the vulgar “according to both the Roman and the Monastic rite”. And to effect this double usefulness, there is an explanation on pages 152-153, entitled “De flexa in ritu monastico”.

A summary is as follows:

I. With the monks of certain orders, by the flex † it is noted that the voice should be lowered by either a major second or a minor third. Also of note, this flex is not to be found, except in the first half of a verse.

II. In the monastic rite, however, there are a certain number of psalm-verses which are not divided in the same manner as in the Roman. This book divides these the Roman way. [I think this is what the sentence is getting at; at any rate, it is true.] But if you want to divide them monastically, below are given all the verses in which there is a discrepancy, (and they are few enough) divided in this manner.

III. Note about all of these verses. — In either rite, to wit, Roman or monastic, these verses consist of three members. But in the Roman, after the first member there is placed the middle cadence, and after the second a pause ; however, in the monastic after the first member there is placed a flex (similar to the pause), and after the second the middle cadence ; which is the reverse order.